Molecular orbital octahedral complex

Fig. 2. Simplified molecular orbital diagram for a low spia octahedral complex, such as [Co(NH3 )g, where A = energy difference a, e, and t may be antisymmetric (subscript ungerade) or centrosymmetric (subscript, gerade) symmetry orbitals. See text.

Figure 19.14 Molecular orbital diagram for an octahedral complex of a first series transition metal (only a interactions are considered in this simplified diagram).

FIGURE 16.36 I1ie tear-shaped objects are representations of the six ligand atomic orbitals that are used to build the molecular orbitals of an octahedral complex in ligand field theory. They might represent s- or p-orbitals on the ligands or hybrids of the two. 

We are now ready to apply the ideas in the preceding three sections to the construction of molecular orbitals in octahedral complexes. 

Fig. 4.4 Molecular orbital diagram for octahedral complexes (cr-interaction only)...

A quantitative consideration on the origin of the EFG should be based on reliable results from molecular orbital or DPT calculations, as pointed out in detail in Chap. 5. For a qualitative discussion, however, it will suffice to use the easy-to-handle one-electron approximation of the crystal field model. In this framework, it is easy to realize that in nickel(II) complexes of Oh and symmetry and in tetragonally distorted octahedral nickel(II) complexes, no valence electron contribution to the EFG should be expected (cf. Fig. 7.7 and Table 4.2). A temperature-dependent valence electron contribution is to be expected in distorted tetrahedral nickel(n) complexes for tetragonal distortion, e.g., Fzz = (4/7)e(r )3 for com-... 

Molecules with two or more unpaired electrons may be divided into two classes by far the most common examples are molecules where the unpaired electrons are contained in a set of degenerate atomic or molecular orbitals with qualitatively similar spatial distributions, e.g., an octahedral Cr(m) (4A2g) or Ni(n) (3A2g) complex, a ground state triplet molecule like 02, or the excited triplet states of naphthalene or benzophenone. 

Figure 5 Schematic presentation of a molecular orbital diagram for an octahedral d6 metal complex involving 2,2 -bipyridyl-type ligands, in which various possible transitions are indicated.

Fig. 13. Molecular orbital scheme for octahedral fluoride complexes...

FIGU RE 17.14 The coordinate system to designate orbitals used in constructing molecular orbitals for an octahedral complex. 

When describing a complex in terms of molecular orbitals, we need to establish a model by which we can identify the orbitals utilized by both the metal and the ligands. We will first consider an octahedral complex with the positions of the ligands identified on the coordinate system shown in Figure 17.14, and the orbitals will be designated by the numbers assigned to the ligands in the positions indicated. 

FIGURE 17.16 Ihe molecular orbital energy level diagram for an octahedral complex. 

Although we will not write the complete wave functions as we did for the case of an octahedral complex, the molecular orbitals give rise to the energy level diagram shown in Figure 17.20. 

FIGURE 18.9 Interpretation of M—charge transfer absorption in an octahedral complex using a modified molecular orbital diagram.The transitions are from e or t2g orbitals on the metal to orbitals on the ligands. 

The molecular orbital model can also be applied to complexes of the d-block elements. In octahedral complexes the d-orbitals of the metal are not degenerate, as they are in the free metal, because of the interaction between the ligand and metal orbitals. The five d-orbitals are split into three t2g (nonbonding) and two e (antibonding) MOs that is ... 

Figure 1.8 Molecular orbital diagram for an octahedral d-block metal complex ML6. The vertical arrows indicate different types of electron transition that may be brought about by photon absorption...

FIG. 10.4 The molecular orbitals of an octahedral ML6 complex where L is an arbitrary e-donor ligand. Source Albright et al. (1985). 

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